Percussive hand-tool.



4 SHEETS-SHEET 1.

No. `845,905. PATENTED MAR. 5, 1907. H. B. STOCKS & J. R. WEBB, JR.

PERGUSSIVE HAND TOOL. APPLICATION FILED SEPT/28,1903,

TH: Numels Erg-Rs ca., wAsMlNaroN, n. cA

N0.'845,9o5. PATENTED MAB.. 5. 1907. H. B. STOCKS @E J. R. WEBB, lJR.

4 SHEETS-SHEET 2.

IERCUSSIVEA HAND TOOL.

APBLIOATION FILED sBPT.2s.19oe.

1H: Hormis PETERs co.. wAsmNcmN, D. c.

No. 845,905. PATENTEDMAR. 5, 1907. H. B. STOCKS n J. R. WEBB, JR.

PERGSSIVE HAND TOOL.

APPLIOMKIION FILED sBPT`.2a.19o.

4 SHEETS-SHEET 3.

1HE Namzls PETERS ca., wAsHlNafoN, n. x2.

No .F845

PATENTBD MABL, 1907. H. B. STOCKS & J. R. WEBB, JR.

PEROUSSIVE HAND TOOL.

- APPLIOATION FILED sEPT.2s.19o6.

4 SHEETS-SHEET 4.

UNITED STATES PATENT OFFICE.

HARRY BENWELL STOCKS AND JOHN RACKER WVEBB, JR., OF MANCHESTER,

ENGLAND, ASSIGN ORS TO THE CLIMAX PATENTS LIMITED, OF MAN- CHESTER,ENGLAND.

PERCUSSIVE HAN D-TOOL.

Specification of Letters Patent.

Patented March 5, 1907.

inclination filed September 28,1906. Serial No. 336,582.

.T (lr/ZZ whom t may concern:

Be it known that we, HARRY BENWELL STOoKsand JOHN RACKER l/VEBB, Jr.,subtuated by compressed air in which a piston l or tup reciprocateswithin a cylinder, as 1s well understood.

Under our invention we use two continuous streams of air under pressurefor the blow and return stroke, and we also employ a valve governing theadmission of motive fluid to the piston of the hammer, such valve havinga small area on which motive iiuid is constantly acting, tending toforce the valve over in one direction, and a large area on which motivefiuid intermittently acts to move the valve at the required times in thecontrary direction.

l/Ve are aware that the principle set out in the preceding sentence isnot novel g but the essential novel feature of our invention, inaddition to the particular construction and operation of .the valve andsystem of ports, consists in the employment of a continuous streamof'air under high pressure for the blow stroke and a continuous streamof air under low pressure for the return stroke, so that the hammerworks economically and with an absence of vibration and shock or jar.

We may under our invention construct the hammer so that the air underhigh pressure is admitted behind the piston for the whole of the blowstroke, or with a modification in detail suchv air under high pressuremay be cut o'lfwhen the piston has made but a portion of its stroke, theremainder of the stroke being worked by the expansive power of theadmitted fluid. We could also use either air under high pressure or airunder low pressure for constantly loading the smaller area cf the valvegoverning the admission of motive fluid to the tool.

l tion'of its blow stroke.

In the accompanying drawings, Figure l represents asectional elevationon the line A B, Fig. 2, of a percussive hand-tool constructed inaccordance with our invention, in which the valve is loaded constantlyon its smaller area with air under high pressure. Fig. 2 is a sectionalplan thereof. Figs. 3 and 4 are respectively sectional elevation andsectional plan of a similar hammer, but provided with an expansion-valveto cut off air under high pressure when the piston has made but a por-Figs. 5 and 6 are sectional elevation and plan of a percussivelhand-tool in which a single valve only is used loaded constantly on itssmaller area with air under low pressure; and Figs. 7 and 8 are similarsectional elevation and plan of a percussive hand-tool similar to Figs.5 and 6, but provided with an expansion-valve.

It will be noted in the percussive handtools illustrated in theaccompanying drawings like parts are similarly lettered to avoidrepetition of description of these parts.

I/Ve will refer first to Figs. l and 2, in which the valve is loadedconstantly on its smaller area with air under high pressure. The toolconsists of a cylinder a., in whichis freely slidable a piston b,provided with an annular recess c at its rear end. The cylinder o issecured to the boss d of the handle c by means of a screwed nut f,bearing against a flange g on the inner end of the cylinder, the iange gcontacting with a disk h, interposed between the flange g and avalve-box t', contained in the boss d of the handle e. The mouth of thecylinder a is provided with a bush to carry the end of a chisel 7c orother tool. The meeting faces of the end of the valve-box i and the bossd of the handle f are formed to provide concentric annular recesses m n.A tube 0, conducting air under high pressure, is secured to the inlet oin the handle, and another tube p to conduct air under low pressure isconnected at p to thel handle. From 0 a passage g connects with theannular recess m, and a similar passage r connects p with the recess n.Each of the passages g r is governed by a piston-valve s, slidable in achamber s', the lower end of which is closed by a screwed plug s2. Atrigger t is mounted on a fulcrum a, the trigger being disposed betweenthe valves s s. This trigger is provided with a horn o, through whichand pro- ICO jeeting from each side thereof is a cross-pin w, disposedon the top ot the valves s s. Normally the air under pressure in theconducting-tubes is sutlicient to maintain the valves s s in theelevated position shown in Fig. l. When pressure is applied upon thevalves 8 s by means et the trigger t, the valves are depressed, andcommunication is established between the passages o p and ports g r, sothat air under high and low pressures is conducted to the annulargrooves m n, respectively, the groove m containing air under highpressure and the groove n air under low pressure. distribution-valve islitted capable et a sliding movement to a certain extent. rlilis valvefr; is vformed hollow with exhaust-passages y `formed therein. lt is ottwo dii'leu ent diameters to 'term a shoulder e, and also an annulargroove 2 is provided near lie end in the smaller diameter. Ports are'termed in. the valve-box i, communicating with tle high and lowair-pressure recesses m n, witlthe valve x, and with ports leading tothe front and rear ot the piston l). As shown in Fig. 2, the piston l)is at the inner end olt its stroke and the valve a; is in correctposition to admit air under high pressure (assuming the valves s s to bedepressedby the trigger t) to the b ack ot the piston tor the blowstroke. Air under high pressure is constantly acting on the small area.e of the valve such air und er pressure being admitted to tlc area e`from the groove m via the ports 3 and 4, forcing the valve a over intothe position shown in Fig. 2. The reduced diameter ot tl'e valve Qcenables air under high pressure to pass to the port or ports 5 and fromthence tltrough the hole or holes 6 in the disk 71y to tle back oit thepiston l), actuating the piston tor tlte blow stroke, the residual airunder pressure o'l the previous return stroke in trent of tle pistonexhausting through the port 7 out ot the aperture 8 at the inner end otsuch port 7, uncovered by tle valve x to the exhaustpassage 9 in thehandle of the tool, and so to atmosphere. lhen the piston l) is justattaining the end ot its blow stroke, tlte annular recess c uncovers theentrance 10 to a port 11, which port 11 is then put into coml municationwith the cavitym, containing air 'under high pressure, by means et theport f3,

so that air under high pressure is admitted to the tront or large area12 ot the valve :11, overcoming the air under high pressure actingconstantly on the small area e' and moving the valve ac into theposition shown in Fig. 1 Air under low pressure can tlen pass trom therecess n tlirough the port 13 in tle valvebox i, around the annulargroove 2 in the valve to the groove 18, and by way ol" the port S to theport 7 tlirou the hole 7l in tlc disk 71 and so to the `trent ot tl'iepiston l), returning the piston to the position shown in Fig. 2. On thereturn stroke of the piston l) ln the valvewbox i a eaaees residual airof the previous blow stroke is exhausted through the aperture orapertures (l in the disk 71. and the port or ports 5 to the annulargroove ltytrom which it passes through the exhaust-ports 1 1/ throughthe hollow valve :l: to the exhaust S), and so to atmosphere. rlo enablethe air under high pressure acting con stantly on the small area .z otthe valve a: to return the valve x to the position shown in Fig. tor thei'-.ext blow stroke, the port 1.1V is continued. forward and is providedwith an outlet 13b into the cylinder c. This outlet 13h is uncoveredwhen the piston l) is attain.- ing the end ot its return stroke, and theair under high pressure previously admitted to act on the large area 12ot the valve a; exhausts into the cylinder a, bringing about sueh areduction ot pressure against the area 12 o't the valve x that the airunder high pressure constantly acting on the small area .e is en abledto move the valve a: over in the position shown in Fig. 2, and. thedescribed cycle ol operations tor the blow and return strokes isrepeated. The hammer is automatically self-starting, tor suppose whenthe air under di'tlerent pressures is admitted by the valves s s thepiston l) should be in the position shown in Fig. 1 ,while the valve :I:is in the position illustrated by Fig. 2, the air under high pressurewould p ass round the annular groove c in the piston l) and be conductedby the port 1 1 to the iront or large area 1.2 on the valve rr, toreingit back to the correct position shown in Fig. 1 to admit air u nderlowpressure Ytor the return stroke. (ln the contrary, should the piston l)be ready 'l'or the blow stroke, as shown in Fig. 2, and the valve a; bein the po sition. indicated. in Fig. l air under high p res sure, whichconstantly acts on the small area e', would as soon as admitted by thevalve s ilorce the valve .r 'forward to the correct position illustratedby Fig. 2.

With a hammer constructed as described the air under high pressure isadmitted behind the piston l) during the whole ot the blow stroke, butwe may provide means, as illustrated in Figs. 3 and Ll, tor cuttingo'llI the air rnder high pressure when the piston has made but a portionot its stroke, so that the remainder ot the stroke would be completed bythe expansive action ot the admitted air under high pressure. To ell'eetthis, we provide the valve-box i with an expansionfalve 15, consistingot a ring ot metal with equal areas 15" 15'y and 'formed withanii'iternal annular recess 1.6, the valve 15 being slidahle'fluid-tight on a seat prepared Vtor it in lthe valve-box, asillustrated. Air under lovY pressure vtrom the port 13 acts eonstanlllvagainst the area 15h ot the valve 15, as will be seen trom an inspectionot Fig. its shown :in Fig. 4, the valve .r has been moved 'forward byair under high pressure acting constantly. as explained, on the smallarea e, and the v: lve 15 has also been moved forward by the air llOunder low pressure. The air under high pressure is thus admitted fromthe ports 3 4 to the groove 5a, and by a port or ports 20 to the recess16 in the valve 15 and a port or ports 21 to ports 22 through holes 23in the disk h, and thus behind the piston b. When half or any otherpredetermined portion of the blow stroke has been completed, a hole 17in the cylinder (see Fig. 3) is uncovered by the piston b, and the airunder high pressure behind the piston enters a port 18 and is conductedby a passage 19 in the disk h to the front area 15a of theexpansion-valve 15, forcing it back against the air under low pressureacting on the area 15b into the position shown in Fig. 3, and thuscutting off the supply of high-pressure air to the back of the piston b.The remainder of the stroke is thus completed by the expansive force ofthe admitted air under high pressure. The air of the previous returnstroke in front of the piston b is exhausted through the port 7 toatmosphere through the exhaust-outlet 9, as already described withreference to Figs. 1 and 2. For the return stroke the valve is movedbackward into the position shown in Fig. 3 by high-pressure air admittedto the ont or large area 12 of the valve via the ports 3, 1.0, and 11,as previously described when referring to Figs. 1 and 2. Air under lowpressure is then admitted through the port `13 and annular groove 2 tothe annular recess 13, to the ports 8 and 7, to the front of the pistonb, returning the piston for the next blow stroke. On the return strokeof the piston l the residual airpressure of the previous blow strokebehind the piston b is swept out through the holes 23 in the disk h,ports 22, to the ports`21, and from thence through the holes 'y to theinterior of the valve and so to atmosphere through the exhaust-outlet 9,as clearly seen in Fig. 3. f

It has already been explained, when referring to Figs. 1 and 2, how theair under high pressure acting on the large area 12 of the valve isreduced sufficiently to enable the valve to be forced forward by the airunder high pressure acting constantly on the small area .2 of the valvein readiness to admit air under high pressure behind the piston b forthe blow stroke and to exhaust the forward end of the cylinder a. In theconstruction shown in Figs. 3 and 4 it is necessary to also move theexpansion-valve 15 forward again into the position indicated in Fig. 4.This is effected by providing the port 18 with an outlet 19EL into thecylinder a, such outlet being uncovered when the piston b has completedits inward stroke, so that air under high pressure admitted to the frontarea 15a of the expansion-valve is reduced in pressure by exhaustinginto the forward end of the cylinder a, which at this instant is placedin communication with the atmos- 5 phere by the forward movement of thevalve l fr, as previously explained. Air under low pressure which isconstantly admitted behind the area 15b of the expansion-valve 15 viathe port 13 is thus venabled to force the expansion-valve forward toenable it to admit high-pressure fluid behind the piston b for the blowstroke.

We do not confine ourselves to the use of air under high pressure forconstantly loading the small area of the distribution-valve as the airunder low pressure used for returning the piston b within the cylinder amay be employed, as illustrated in the construction, Figs. 5 to S. InFigs. 5 and 6, which we will first deal with, no expansion-valve isused, the distribution-valve admitting air under high pressure behindthe piston l) throughout the entire blow stroke. For the return Astrokethe valve :v and piston l) are in the relative positions shown in Fig.5. The valve is formed with two annular grooves 2 and 2a. Air under lowpressure passes from the annular groove n along the port 13,-

around the annular groove 2a in the valve :c to the groove 13a, and tothe port 7 to return the piston. Air previously supplied behind thepiston is exhausted through the holes 6 in the disk 7L and ports 5 tothe annular groove 14, and from thence through the holes y to theinterior of the valve and from thence to atmosphere by the exhaust 9. Asthe piston attains the end of its return stroke the port 11 permits airunder pressure on the large area 12 of the valve :r to exhaust into thecylinder a, and from thence by a hole 23 to atmosphere. This reduces thepressure on the large area 12 of the valve a: to atmospheric, orthereabout, and enables air under low pressure acting constantly on theshoulder or small area z of the valve to move the valve forward in theposition shown -in Fig. 6. Thus air under high pressure can pass fromthe groove m through the ports 3 and 4, around the annular groove 2 tothe port 5, and thus behind the piston for the blow stroke. The airunder pressure of the previous stroke in front of the piston exhauststhrough the ports 7 and S to the exhaust 9, and sov to atmosphere. Whenthe blow stroke is completed, air under high pressure is conducted fromthe port 3 around the annular recess c in the piston Z) through theports 1.0 11 behind the large area 12 of the valve c, forcing itbackward into the position shown in Fig. to admit air under low pressurein front of the piston b for the return stroke.

Figs. 7 and 8 show a similar hammer to Figs. 5 and 6, but having anexpansion-valve constructed and applied in manner similar to that inFigs. 3 and 4. As shown in Fig. 7, the return stroke of the piston b andthe exhausting of air under pressure behind the piston is effected asdescribed with reference to Fig.5 and can be readily followed. Vhen IOOIIO

IIS

the piston l) has been returned. to the position shown in Fig S, airunder pressure in front of the area 15 of the expansion-valve l5 and airunder pressure acting` on the large area l2 of the valve fr exhaustsinto the cylinder e through the ports 1.1 1S, and fromY thence toatmosphere through the hole 23 in the cylinder, so that alr under lowpressure acting on the rear area 15b of the expansion-valve 15 and alsoon the small area z ol the distribution-valve is enabled to move boththese valves 'forward into the position shown in Fig. 8. The cylinder a,behind the piston l), is then open to admit air un der high pressure forthe blow stroke, as will be apparent. Air under pressure in front of thepiston l) is exhausted to atmosphere on the blow stroke through theports 7, S, and 9. Vilben a portion ol' the blow stroke has beenellected, the air under high pressure admitted to the cylinder a behindthe piston passes through the ports 17, 18, and 19 to the liront area15a of the expansion-valve 15, 'forcing it b ackward to the positionshown in Fig. 7 and cutting oil. the supply of air under high pressure,so that the remainder of the stroke is completed by the expansivepressure of the air under high pressure admitted behind the piston.

It will be understood that the motive [luid for the blow stroke may beair under any desired pressure in excess o'l' the pressure used lor thereturn stroke and the air under low pressure such as will be sullicientto promptly return the piston in the cylinder in readiness for the blowstroke.

The drawings show the inventirui applied to a percussive liand-tool, butthe invention may be used with larger power-hammers aetuated by airunder pressure.

We declare that what we claim is l. ln percussive hand-tools,power-hammers and similar tools in which a piston or tup is reciprecatedto and fro within a cylinder, inlet-ports conducting two continuousstreams ol air, one under high {nessure l'or the blow stroke and oneunder low pressure for the return stroke, in combination with adistribution-valve having two unequal areas, the small area beingconstantly acted upon by air under pressure and the large area beingintermittently acted. upon by air under pressure substantially asdescribed.

2. In percussive hand-tools, power-hammers and similar tools in which aiston or tup is reeiprooated to and 'lire within cylinder, inlet-portsconducting two continuous streams of air under pressure, one under highpressure for the blew stro re and one urder low pressure for the returnstroke, iu combii nation. with a distribution-valve havin g two unequalareas, the small area being constantly acted upon by air under)ji'iji'essure and the large area being intermittently acted upon by airunder pressure, with means lor cutting ell admission of air under highpres- `valve to lio'rm dill sure wlren the piston has made but a portionol its stroke substantially as described.

ln a perrussive hard-tool, power-hammer or similarI tool, a cylinder, apistou slidable within sueh cyliider, inlet-ports lor lu'o continuousstreams ol air iuder dillereiu pressures, a valve-box, a hollowdisl'riluuiouvalve el' unequal diameters slidable in such valve-boxformed with exiiaust-passages, uuequal areas lormed on such valve tolorm dill'erei'ilial pressure areas, ports to conduct constantly airunder pressure to the smaller pressure area ol" the valve, portsgoverned by the piston to conduct intermitlently air under pressure tothe larger area el` tlze valve. an exhaust-port to atmosphere, 'portsliormed in the cylinder comniuuicatiizg with the distributioii-valve andvalve-box, substaiitially as desoribed.

l. ln a percussive hand-tool or the like. a cylinder, a pis i slidablewithin suoli cylinder, inlet-ports 'lor two continuous streams et airunder dill'erent pressures, a valve-bex, a hollow distribillion-valve elunequal diameters slidable therein lormed with exhaustpass'iages,unequal areas 'formed on sucia Iereul'ial pressure aras. ports toconduct constantly air under pressure to the smaller areay ol the valve,pons governed by the pil. in to conduct intermittently air underpressure to the larger at ol the valve, an expansioir-valve slidable inl ee valve-box, ports to eoiiduct air under low pressure oorustantly toone atea olt the expansion-valve, ports governed by the piston tooonduet air urder high pressure iulermitently to the other area ol theexpansionvalve, an exhaust-port to atmosphre, ports formed in thecylinder eommuuiealing with the valves, and valve-box, substantially asdeseri bed.

5. A pou/er-hamn'ier consisting ot a evliuder, means `for carrying atool in the nuiui ii el the cylinder, a piston slidable in. the\linzler, a recess formed in the rear end olA sutil piston, a handleseeured to the cylinder, a valve-box within sueh liaiulle, a disk serured betul'een the eylinder end and the vulve-box. a hollowdistribution-valve el unequal diameters slidable within the valve-box,exhaust-passages in such valve and au annular recess, uneipral areas onthe valve to l'oriu two differential pressure areas, an exhaustpassagecommunirating with the hollow distributien-valve and to atmosphere,inleiporl's in the handle lor two eonlinno-osl streams ol" air underhigh airl low pressure, throttle-valves governing suoli inlets aud Vmea'lier operating tue tlufottle-valvos, ports to con: uol'I :,onstaruilyair under liigi pressure to the smaller areay et the distribution-valveto aetuate the valve in. one dire#- l'iiin, ports governed by thedis'itribulwuvalve to conduct air under liigh pressure behind the pistonfor the blow stroke, ports l 'dfi under high pressure at the end of theblow stroke around the annular recess in the rear of the piston to thelarger area of the distribution-valve to actuate the valve in thecontrary direction, ports governed by the distribution-valve to conductair under low pressure in front ofthe piston for the return stroke,ports governed by the distributionvalve to exhaust air behind the pistonto atmosphere, and ports governed by the piston to exhaust air underpressure acting on the larger area of the distribution-valve, at the endof the return stroke substantially as described.

6. A power-hammer consisting of a cylinder, means for carrying a tool inthe mouth of the cylinder, a piston slidable in the cylinder, a recessformed in the rear end of such piston, a handle secured to the cylinder,a valve-box within such handle, a disk secured between the cylinder endand the valve-box, a hollow distribution-valve of unequal diametersslidable within the valve-box, exhaust-passages in such valve, and anannular recess, unequal areas on the valve to form two differentialpressure areas, an exhaust-passage communicating with the hollowdistribution-valve and to atmosphere, inlet-ports in the handle for twocontinuous streams of air under high and low pressure, throttle-valves,governing such inlets and means for operating the throttle-valves, portsto conduct constantly air under high pressure to the smaller area of thedistribution-valve to actuate the valve in one direction, anexpansion-valve slidable in the valvebox, equal pressure areas at eachend of such expansion-valve, ports to conduct constantly air under lowpressure to the rear oi such expansion-valve, ports governed by thedistribution-valve to conduct air under high pressure behind the pistonfor the blow stroke, ports governed by the piston to conduct air underhigh pressure admitted behind the piston to the front pressure area ofthe expansion-valve to move the valve backward and cut off the admissionof air under high pressure behind the piston when the piston has madebut a portion of the blow stroke, ports governed by thedistributionvalve to exhaust air under pressure in front of the pistonto atmosphere, ports governed by piston to admit air under high pressurearound the recess in the rear of the piston to the larger area of thedistribution-valve to HARRY BENWELL STOCKS.- JOHN RACKER WEBB, JUNIOR.

Witnesses:

NORMAN KIERNAN, HUBERT BUx'roN JAMESON.

